@article{ClassifyingComplexity,
  author = "Andrei Bulatov and Peter Jeavons and Andrei Krokhin",
  journal = "SIAM Journal on Computing",
  number = "34",
  pages = "720--742",
  title = "Classifying the complexity of constraints using finite algebras",
  url = "http://web.comlab.ox.ac.uk/oucl/research/areas/constraints/publications/SIAMclassifying.pdf",
  year = "2005",
}